The present invention relates to the field of perfumery. It relates, more particularly, to .alpha.-keto esters, as defined below, of alcohols which are precursors of fragrant aldehydes and ketones and which are capable of releasing said fragrant ketone or aldehyde upon exposure to light, more particularly daylight. Said .alpha.-keto esters may furthermore contain, in .alpha.-position to the keto group, an alkyl group which may contain various substituents and which alkyl group is derived from a fragrant molecule possessing an olefinic unsaturation. The unsaturated molecule and/or the aldehyde or ketone are released upon exposure to light, in particular daylight, of the .alpha.-keto ester.
There exists, in perfumery, a particular interest in compounds which are capable of "fixing" fragrant molecules, for example by chemical bonding or intramolecular forces like absorption, and releasing said fragrant molecules over a prolonged period of time, for example by the action of heat, enzymes, or even sunlight. Fragrant molecules have to be volatile in order to be perceived. Although many fragrant compounds are known which show a good substantivity, i.e. they will remain on a surface to which they have been applied for several days and can hence be perceived over such a period of time, a great number of fragrant compounds are very volatile, and their characteristic smell can no longer be perceived several hours after their application.
It is thus desirable to dispose of fragrance delivery systems which are capable of releasing the fragrant compound or compounds in a controlled manner, maintaining a desired smell over a prolonged period of time.